KR102356415B1 - Method for producing at least one recess in a material by means of electromagnetic radiation and subsequent etching process - Google Patents

Abstract

The present invention relates to a method for introducing at least one through-hole (1) into a transparent or transmissive glass substrate (2), said glass substrate (2) selectively using electromagnetic radiation, in particular a laser, along a beam axis (s) is modulated to The modulations are generated in the glass substrate 2 along the beam axis s by electromagnetic radiation having different properties, for example by different pulse energies, such that the etching process in the glass substrate 2 is non-homogeneously with each other. It goes with different etch rates. Thereby, in the transparent or transmissive material, a through-hole (1) resulting on the basis of an etching process is targeted and optionally formed via the different properties of the modulations and, for example, the cone angle (α, The possibility of changing β) is created.

Description

METHOD FOR PRODUCING AT LEAST ONE RECESS IN A MATERIAL BY MEANS OF ELECTROMAGNETIC RADIATION AND SUBSEQUENT ETCHING PROCESS

The present invention relates to a method for introducing at least one recess, in particular a through-hole, into a transparent or transmissive, in particular plate-shaped, material, wherein the material is formed along a beam axis with electromagnetic radiation, in particular a laser. Selectively modulated, the recesses are subsequently created by an etching process, resulting in different etching rates in the modulated and unmodulated regions.

WO 2016/041544 A1 discloses such a method for introducing at least one recess into a plate-shaped workpiece, in particular as a through-hole. For this purpose, laser radiation is directed at the surface of the workpiece. The duration of action of the laser radiation is chosen to be very short, so that only modulation of the workpiece takes place concentrically around the beam axis of the laser beam. In the next method step, anisotropic material removal takes place by etching sequentially based on the action of the etchant, first in the areas of the workpiece that have undergone modulation by means of a laser beam. In this way, a recess is created in the workpiece as a through-hole along the cylindrical working zone. In particular, the defect regions generated in the first step are sequentially enlarged, thereby creating a recess or a through hole. An essential advantage of this method is that the modulation zone extends coaxially to the beam axis in an essentially cylindrical shape, thus resulting in a constant diameter of the through-hole or of the recess.

It is known from DE 10 2010 025 966 B4 that in a first step a focused laser impulse is directed onto a glass workpiece, the light intensity of which is strong enough to cause localized non-thermal destruction along one channel in the glass.

A method for processing glass through the production of filaments is also known from US 2013/126573 A1.

Also, for creating structures in glass, etching methods, such as lithography, have long been known. At this time, the coating is irradiated and subsequently opened locally. Subsequently, the substrate is etched to create the desired structures. The coating is then used as an etching resist. However, since etching etching is isotropically performed in the areas where the resist was open, structures having a large aspect ratio cannot be produced.

It is an object of the invention to create the possibility of modulating the material by means of electromagnetic radiation so as to realize the desired, in particular selectively different removal of the recesses in the subsequent etching process, and thus also recesses with in particular different opening angles. .

This object is achieved according to the invention with a method according to the features of claim 1 . Other implementations of the invention may be derived from the dependent claims.

That is, according to the invention, modulations with different properties are generated by electromagnetic radiation in the material along the beam axis, for example by different pulse energies, so that the etching process in the material proceeds non-homogeneously, through which the A method is provided, wherein the etch rate in modulated regions is different in modulated regions with said different properties under otherwise unchanged etch conditions. In this way, according to the invention, the possibility is created for setting recesses, in particular through-holes, which arise on the basis of an etching process in a transparent or transmissive material, by targeting and optionally via the different properties of the modulations. Thus, for example, the enlargement of the recess does not result from a longer etch etch, but rather on the basis of a faster etch removal depending on the different properties of the modulations. At this time, according to the present invention, not only conical enlargements can be generated in the edge regions close to the surface. On the contrary, such magnifications can be inhibited, for example, in order to create cylindrical or convex recesses, whereby the properties of the modulations are set such that in the region between the surfaces of the material a favorable etch away occurs there.

Here, the different properties of the modulations have proven particularly promising if, in particular, using phase modulation is achieved through a change in the beam shape of the electromagnetic radiation. In this way, the change in properties can be carried out in an uninterrupted working step during the processing of the material, so that the processing can be carried out as much as possible without undesirable delays.

In addition, the different properties of the modulations are achieved through a change in process parameters, in particular of the focal position, of the pulse energy, of the beam shape and/or of the intensity, so that the change can be realized at relatively low cost in operation of the process. If so, it likewise has proven particularly promising.

Other, likewise particularly purposeful implementations of the invention are achieved even when a cycle consisting of modulation and etching of the material is carried out several times. That is, the re-modulation of the material is performed after the first etching treatment, so that, for example, the post-processing can be performed with higher accuracy. In particular, with respect to etch processes with small etch rates, such removal can be targeted, controlled, and terminated when desired target values are reached.

Here, a number of etching steps have proven particularly fit for purpose, especially if they are carried out, with different etching conditions, and thus reach an optimum in the removal performance on the one hand and an achievable accuracy on the other hand.

It has also already proven advantageous if one surface of the material, in particular plate-shaped, is covered at least in some sections with an etching resist, thereby being protected from etching corrosion in subsequent etching methods. This allows the etch rate to be targeted through a one-sided etch erosion and concentrated on the free surface, where enhanced removal is desired.

Particularly preferably, the opening angle or the diameter of the recess can be arbitrarily set, in particular smaller than 5°, through the selection of process parameters, wherein the difference between the opening angles is based on the modulations having different properties. may exceed 10°.

Further, the recesses may be created such that the diameter and/or shape of the recesses differ from each other by up to 3 μm.

As plate-shaped, transparent or transmissive material to electromagnetic radiation, various materials can be used, wherein said in particular plate-shaped material preferably has glass, silicon and/or sapphire as essential material parts, Through this, it has excellent physical and chemical resistance, which is optimally suitable for various technical application purposes.

The invention is not limited to specific areas of application. Particularly preferably, there is provided the use of the plate-shaped material produced according to the method as a nozzle plate of a printing apparatus.

The present invention allows for several embodiments. In order to make the basic principle thereof more clear, one of the embodiments is shown in the drawings and described below.

1 schematically shows a cut side view of a glass substrate provided with through holes;
2 schematically shows the different modulation types;
3 schematically shows various method steps when using an etching resist.

1 shows a cutaway side view of a glass substrate 2 as a material provided with through-holes 1, manufactured according to a method according to the invention. An essential advantage of the invention in its manufacturing method relates to the individual and settable variation of the cone angles α, β of the through-holes 1 in the glass substrate 2 .

As can be seen, for the first time with the method according to the invention, with respect to the respective outer surfaces of the material on the one hand a small cone angle α of less than 2°, on the other hand on the opposite side Through-holes 1 having a large cone angle β of about 20° are provided in the glass substrate 2 .

To this end, in a first step, for example, 100 μm thick glass is modulated with the radiation of the laser system as glass substrate 2 . Depending on the power introduced into the glass, different intensity modulations of the glass substrate 2 can be set.

Hereinafter, the different modulations shown in FIG. 2 are referred to as “Type I” or “Type II”. A “Type I” modulation here indicates less alteration of the glass, and the alteration is likewise produced by less laser power. “Type II” modulations are correspondingly strong modifications of the glass structure, brought about by higher laser power.

With the very high positioning accuracy of the facility, not only the focal length of the laser lengthened by means of optical aids but also the focal length position in the glass substrate 2 can be defined very precisely.

In principle, “Type I” and “Type II” modulations in the variation shown on the left in FIG. 2 can be achieved with two or more laser pulses LP1, LP2 or correspondingly the variation shown on the right Modulation in α can be achieved with one and only one laser pulse.

The transition from “Type I” modulation (low power) to “Type II” modulation (high power) can thus already be realized along the diffusion direction of the laser taking into account the power profile via one individual pulse.

To enhance this effect and to increase the difference between the two modulation types, after a first uniform “Type I” modulation along the entire glass, a second pulse of increased power and with an altered focal length position can be used. .

In the second process step shown in Fig. 3, one side of the glass substrate is covered with a cover resistant to hydrofluoric acid, such as an adhesive film as an etching resist (R), so that in the subsequent etching step (a), the modulation Only one type is etched. After removing the etching resist (R) in the process step (b), the etching step (b) is performed again, whereby both sides of the glass substrate are etched. The variations (I, II) are distinguished by the arrangement of the etching resist (R), whereas in the variation (III) the etching resist is omitted.

Since the two modulation types are etched in hydrofluoric acid at different rates, different cone angles (α, β), shown in FIG. 1 , result therefrom. First, one side is etched in advance, so that one side difference in hole diameter can be set.

In the second etching step, the through holes 1 may be enlarged. Corresponding to the schematic shown, thus arbitrarily different geometries can be realized.

The following wet-chemical solutions were realized as etchants:

Hydrofluoric acid:

- Concentration: 1 -20 %

- Temperature: 5 - 40℃

- Second acid: H2SO4, HCL, H3PO4

Potassium hydroxide:

- Concentration: 10 - 60 %

- Temperature: 85 - 160℃

Unlike the prior art, in this way different cone angles (α, β) and hole diameters can be set on both sides of the glass substrate 2 . The individual geometries of the through-holes 1 can thus be produced, in which case microcracks cannot be unavoidable according to the prior art, in particular by laser drilling. In particular, the cone angles α, β of the through holes 1 can be variable in the cross section of the substrate material. For example, this results in advantages for the manufacture of components for microfluidics.

According to the invention, multiple modulations with different properties can be produced in the glass along the beam axis s, eg penetrating modulations, and chains of small bubbles. In this way, the etch erosion becomes non-homogeneous over the modulation length, ie the etch rate differs, particularly under constant etch conditions.

In this case, the following aspects may be realized in an advantageous manner according to the invention:

여러 가지 영역들에서 에칭조건들의 변경

Change of etching conditions in various areas

양측 또는 일측 에칭 (에칭 레지스트)

Double-sided or one-sided etching (etch resist)

노즐판으로서의 사용

Use as a nozzle plate

모든 구멍들이 동일함, 정확성 < 3㎛

All holes are identical, accuracy < 3㎛

개방각도 < 5°

Opening angle < 5°

개방각도들의 차이 > 10°

Difference in opening angles > 10°

위상 변조 (공간적 광변조기, SLM) 를 이용해 또는 공정파라미터들 (초점 위치, 강도 등등) 을 이용해 서로 다른 변조들이 실현됨

Different modulations are realized using phase modulation (spatial light modulator, SLM) or using process parameters (focal position, intensity, etc.)

Machining, with reference to the drawings below, has a cone angle α of about 15° in the upper region and a cone angle β of about 2° in the lower region two different cone angles in the interior of the through hole. It will be described in detail based on a method example of a process sequence for generating (α, β). First, laser structuring is performed with two laser pulses with different pulse energies, whereby modulations through the entire thickness of the glass substrate 2 and additionally a chain of small bubbles are applied to the upper part of the glass substrate 2 . is created

Subsequently, the glass substrate 2 is coated on one side with a film resistant to hydrofluoric acid, and fixed in a holding frame. After that, etching of the unprotected side from the film is carried out in hydrofluoric acid (1 to 20% HF) at a temperature between 5° C. and 30° C. for 5 to 60 minutes.

Thereafter, the region of the film protecting the region of the recess to be introduced is removed, for example irradiated with UV light in the case of a film implemented as UV-Release-Tape or by heat in the case of a film implemented as a Heat-Release-Tape. processed The film remains in the region of the edge of the recess to be introduced, whereby handling of the glass substrate 2 is improved. After the subsequent re-etching process, the film is completely removed.

Instead of the film, a coating can also be carried out, for example with chromium, wherein a first etching bath is set so that the coating is only removed in the next etching bath.

Further, for example, after the preceding etching treatment, other laser modulation and one or both side etching treatments may also be performed.

Very thin glass substrates 2 having a thickness of less than 100 mu m are preferably fixed in a wafer frame during processing for improved handling, eg attached onto the wafer frame.

Claims (9)

A method for introducing at least one recess into a transparent or transmissive material, comprising:
With electromagnetic radiation the material is selectively modulated along a beam axis s, the recesses are subsequently created by one or several etching steps, in modulated areas and in unmodulated areas one another Different etch rates appear,
Modulations with different properties are produced by the electromagnetic radiation in the material along the same beam axis s, so that the etching process in the material proceeds non-homogeneously, and the etching rates are such that the etching conditions do not change. different for each region modulated with different characteristics,
The different etch rates of regions modulated with different properties have a shape in which the recesses expand into a cone formed in the surface of the transparent or transmissive material, wherein the recesses are formed in the transparent or transmissive material of the material. to have different opening angles (α, β) on opposite surfaces, the difference between the opening angles (α, β) being greater than 10°,
introducing at least one recess into a transparent or transmissive material, characterized in that the different properties of the modulations are achieved using phase modulation and further achieved by varying the process parameters of at least one of pulse energy and intensity way for. The method of claim 1,
The method for introducing at least one recess into a transparent or transmissive material, characterized in that the different properties of the modulations are achieved by further changing the process parameter of the focal position. The method of claim 1,
A method for introducing at least one recess into a transparent or transmissive material, characterized in that a cycle consisting of modulation and etching of the material is carried out several times. The method of claim 1,
A method for introducing at least one recess into a transparent or transmissive material, characterized in that a plurality of etching steps are carried out with different etching conditions. The method of claim 1,
for introducing at least one recess into a transparent or transmissive material, characterized in that one surface of the material is covered at least in some sections with an etching resist, thereby being protected from etching corrosion in subsequent etching methods Way. 6. The method of claim 5,
A method for introducing at least one recess into a transparent or transmissive material, characterized in that the surface of the plate-shaped material is covered with an etching resist. 3. The method of claim 2,
A method for introducing at least one recess into a transparent or transmissive material, characterized in that at least one of the opening angles (α, β) and the diameter of the recess are set through the selection of the process parameters. 8. The method of claim 7,
A method for introducing at least one recess into a transparent or transmissive material, characterized in that the difference in the opening angles (α, β) is due to the modulations having different properties. A printing apparatus having a nozzle plate made of a plate-shaped material manufactured through the method according to any one of claims 1 to 8.

Images